Ultrastructural localization of photosynthetic activity in thylakoids during chloroplast development in maize

Abstract

The localization of photosynthetic activity in developing maize (Zea mays L.) chloroplasts was studied in situ by two electron-microscopic-cytochemical methods. The activity of photosystem I was detected by photooxidation of 3,3'-diaminobenzidine (DAB) and the activity of the photosystem II by photoreduction of thiocarbamyl nitrotetrazolium blue (TCNBT). During the transformation of proplastids into chloroplasts, at the base of the leaf blade the DAB reaction appeared before the TCNBT reaction. A positive DAB reaction was observed in the single thylakoids of plastids in cells located only about 0.5 mm above the base. Dark, osmiophilic DAB polymers accumulated in the lumina of the thylakoids. Plastid envelopes and tubules of the prolamellar bodies in immature chloroplasts were DAB-negative. In fully differentiated leaf tissue the DAB reaction was intense in the thylakoids of bundle-sheath chloroplasts, as well as in the stroma thylakoids and the peripheral grana thylakoids of mesophyll chloroplats. The photoreduction of TCNBT started in leaf tissue about 1 mm above the base. Dark granular material of reduced TCNBT appeared mostly in the partitions of grana, i.e. interthylakoidally, but some granules were also attached to the stroma thylakoids. The membranes of plastid envelopes and the tubules of prolamellar bodies showed a negative TCNBT reaction. Young bundle-sheath chloroplasts contained some reduced TCNBT in their grana; these deposits largely disappeared in the course of further differentiation. In mature leaf tissue the photoreduction of TCNBT was conspicuous in the grana of mesophyll chloroplasts, but very weak in the single thylakoids and in the granal rudiments of bundle-sheath chloroplasts.

Physiological, structural, and immunological characterization of leaf and chloroplast development in cotton

“…These data indicate that the proteins are not artifactually redistributed during processing for microscopy. The appearance of the thylakoid proteins and their relative abundance were different from what one might have expected based upon the previous studies of chloroplast development in etiolated or low-lightgrown plants (Wrischer 1988(Wrischer , 1989. That is, one would have expected an early enrichment in PS-Irelated proteins and the later appearance of PS-IIrelated proteins.…”

“…Further chloroplast development results in larger, more extensively stacked, mature chloroplasts. Studies of intercalary meristems of monocots (e.g., Baker et al 1983), cytochemical studies on developing plastids (Wrischer 1988(Wrischer , 1989, and combined structural and immunofluorescence studies (Robertson et al 1993, Robertson andLeech 1995) have attempted to correlate structure and function in chloroplast development. We have begun a series of structural and physiological investigations of leaf and chloroplast development in field-grown cotton plants (Pettigrew et al 1993).…”

Recovery of maize seedling growth, development and photosynthetic efficiency after initial growth at low temperature

“…2H, I). Already at this stage, the activity of both PS I and PS II is detectable (Wrischer, 1989). The delay in development of photosynthetic efficiency could be related to insufficient growth of roots, taken here as total root length (Fig.…”

bundle sheath defective2, a Mutation That Disrupts the Coordinated Development of Bundle Sheath and Mesophyll Cells in the Maize Leaf

“…As the plastids approach maturity, however, bundle sheath chloroplasts "dedifferentiate" into the agranal structures seen in the mature leaf. This loss of granal stacking in bundle sheath chloroplasts is generally associated with the loss of polypeptides associated with photosystem II activity (Wrischer, 1989;Meierhoff and Westhoff, 1993).…”